by Barbara Canavan*
As I plug away on the prospectus for my doctoral research, I ponder all that I have learned from the history of science and medicine in the past two years. My background and interests have led me to the intersection of history, ecology, virology, climate, infectious disease, and technology. It is humbling to confront the need to bring it all together in a scholarly and unique way. What is the nexus of these diverse topics? All I need to do is to come up with a research question that, when answered, would shed new light on what others have done before…and for that new light to truly have us look at things in a new way. Easy, right? Not so much. Here is my start and I welcome comments.
What has led scientists to examine wild birds as a significant reservoir of diseases that are transmitted to humans? What has happened since the 1950s when a few virologists walked on a beach in Australia and wondered about all the dead shore birds? They considered the unthinkable – could wild bird migrations, one of nature’s most magnificent phenomena, be implicated in the ecology of human influenza viruses?
Avian influenza, or fowl plague, was the first influenza virus to be isolated, in 1900, but fowl plague was not recognized as being caused by a type A influenza virus until 1955, years after the first human influenza virus was isolated in 1933. Then, other avian influenza A viruses were isolated from domestic chickens, turkeys, ducks, and pigeons. The belief was that these bird viruses all originated from human strains of influenza, passed to the birds by their human handlers. There were no reports of influenza viruses isolated from wild birds, and no attempts to do so. Now, after decades of work, it has been argued that wild aquatic birds are indeed the natural hosts of type A influenza and probably have been for many millions of years. Pigs enter the picture as a genetic “mixing vessel” for the mingling and reassortment of viruses from both animals and humans. The result can sometimes be a deadly new influenza A virus.
Although the role of wild birds in the ecology of influenza evokes energetic debates, the magnitude of epidemics (H5N1) has increased the demand for an understanding of the natural history of wild birds. Surveillance over vast spatial and temporal scales calls for international collaboration among researchers in wildlife science, public health, ecology, virology, genetics, and climate. These historical moments, cultural assumptions, science, and technology are central to the history of virology and zoonotic disease. It is a fascinating story that includes cold war science; avian virus research aboard space shuttles; wild geese flying over the Himalayas to pick up pathogenic viruses in Tibet that are transmitted to domestic birds and humans along bird migration routes within Europe and Africa; experiments to make avian flu transmissible among humans; and more. This is not to leave out those scientists who strolled the Australian beaches and managed to engage their scientific community in the quest to understand the boundaries of the ecologies of wild bird and human diseases.
Human societies will remain vulnerable to the continuing processes of pathogen emergence in the centuries to come. Although this future may have no analog from the past, the history of avian influenza reveals that wild birds can provide early warning (as biological sentinels) of emerging infectious diseases for humans. There are interconnections of history, environment, the health of many species, and geopolitics. It is a story of technology and culture within the history of virology intended for historians of science, researchers from diverse fields, and the public.
*Barbara Canavan is a Ph.D. candidate in History of Science at Oregon State University